Sodium orthosilicate

Metasilicic acid, H2Si03, and orthosilicic acid, H4Si04, are weak acids. However, when a solution of sodium orthosilicate is acidified, instead of H4Si04, a gelatinous precipitate of silica is produced ... 

S. Mohanty and S. Khataniar. Sodium orthosilicate an effective additive for alkaline steamflood. J Petrol Sci Eng, 14(l-2) 45-49, December 1995. 

Burk, J.H. "Comparison of Sodium Carbonace, Sodium Hydroxide, and Sodium Orthosilicate for EOR", SPE Reservoir Engineering, February 1987, 10-15. 

Sodium nitroprusside, 74 536 Sodium nonoxynol-25 sulfate cosmetic surfactant, 7 834t Sodium oleoyl isethionate cosmetic surfactant, 7 834t Sodium orthophosphates, 73 8321 Sodium orthosilicates commercial, 22 465, 466t, 469t manufacture of, 22 464, 465 Sodium oxide(s), 2 273, 22 765 in cement, 5 468 contamination by, 22 776 Sodium ozonide, 79 417 Sodium palmitate, as soap, 22 726 Sodium pentaborate... 

Sodium Orthosilicate Sodium Carbonate Trisodium Phosphate Aerosol 22 Surfactant Triton CF-10... 

The US military specifications embodying the requirements for Na silicate are presented in 0-S-604 C (1) for Sodium Metasilicate, Technical (Ref 12a), P-S-651E (1) for Sodium Orthosilicate, Technical (Ref 12b) and O-S-605D for Sodium Silicate Solution (Ref 6a)... 

Sodium orthosilicate, anhydrous 2Na20 Si02 Sodium orthosilicate, hydrate 2Na20 Si02-5H20... 

In our studies, the nano-sized sihca was synthesized using cheap sodium orthosilicate and sodiirm metasihcate rather than expensive alkoxysilanes. An inverse microemulsion containing NP-5/NP-9 as surfactant and cylcohexane or petroleum ether as the oil was used to carry out the hydrolysis and condensation of sodium orthosilicate or metasilicate using an acidic medium [152, 153]. The spherical silica particles of size 10-20 nm were obtained in a system using cyclohexane as the oil and with sodium orthosihcate of 0.01-0.1 M [152]. The particle size increased as the concentration of sodium orthosihcate and the pH were increased. Sihca particles prepared in basic conditions were more uniform in size than those prepared in an acidic medium. But calcined sihca powders with larger specific areas (350-400 mVg) were obtained for those prepared in an acidic medium. 

The most common route for the s5mthesis of magnesium silicate is via a precipitation reaction between a soluble metal silicate (e.g., sodium orthosilicate, sodium metasilicate, or potassium silicate) and a soluble magnesium salt (e.g., magnesium sulfate, nitrate, or chloride). The aqueous suspension of the precipitate is filtered and the collected solid is washed and dried (Fig. 7.2) [6,7]. 

The dissolution process for sodium silicate consists of its hydration with the formation of NaOH. Sodium orthosilicate hydrolyzes according to Eq. (7.1) ... 

A large part of the sodium carbonate consumed (e.g. 50% in the USA) is utilized in the glass industry, of which ca. 40% is used in the manufacture of bottle glass. Sodium carbonate serves both as a raw material and as a flux for the glass melt to dissolve the sand (see Section 5.1.2.2). A further 19% is utilized in the manufacture of chemicals, of which ca. 10% is for the production of sodium phosphates, mainly pentasodium triphosphate, in addition to silicates (sodium metasilicate pentahydrate and sodium orthosilicate), sodium chromate, sodium dichromate, sodium hydrogen carbonate, sodium nitrate etc. About 13.5% is utilized in the soap and detergent industry and 2.5% in the paper and pulp industry. Small quantities of sodium carbonate are necessary in almost all industry... 

The melting point of this Na20 Si02 is 1089 0.5°C [9], and the sodium orthosilicate-sodium metasilicate eutectic is at 41.1 wt % Si02 and 1022°C. 

The primary phase fields that appear on the liquidus surface within the Na20-Al203-Si02 system are cristobalite, tridymite, quartz, sodium disilicates, sodium metasilicate, mullite, corundum, nepheline, carnegieite, albite, and sodium orthosilicate solid solution. 

Derivation Crystals from solutions obtained by heating silica or sodium metasilicate with sodium hydroxide. Intermediate in composition between ortho- and metasilicates, less alkaline than sodium orthosilicate. 

See sodium metasilicate, anhydrous sodium metasilicate pentahydrate sodium sesquisilicate sodium orthosilicate. 

Alkaline flooding is also called caustic flooding. Alkalis used for in situ formation of surfactants include sodium hydroxide, sodium carbonate, sodium orthosilicate, sodium tripolyphosphate, sodium metaborate, ammonium hydroxide, and ammonium carbonate. In the past, the first two were used most often. However, owing to the emulsion and scaling problems observed in Chinese field applications, the tendency now is not to use sodium hydroxide. The dissociation of an alkali results in high pH. For example, NaOH dissociates to yield OH" ... 

Campbell (1981) compared sodium orthosilicate and sodium hydroxide in recovering residual oil. The test results showed that the former was more effective than the latter under the conditions studied, both for continuous flooding and 0.5 PV slug. The mechanisms through which sodium orthosificate produced higher recovery than sodium hydroxide in those tests were not concluded. Reduction in interfacial tension is similar for both chemicals. Other factors must play a more important role. 

Radke and Somerton (1978) investigated the use of a sodium metasilicate (NaaSiOs) buffer in core floods. A metasilicate buffer at a pH of 11.2 showed breakthrough at 2.5 PV injection, whereas sodium hydroxide of the same pH did not appear until a 12 PV injection (Mayer et al., 1983). This result means that sodium metasilicate reaction with rock is much weaker than sodium hydroxide. Chang and Wasan (1980) indicated that there were differences in coalescence behavior and emulsion stability that favor sodium orthosilicate over sodium hydroxide. 

Alkali Formula Sodium Hydroxide NaOH Sodium Carbonate Na2C03 Sodium Orthosilicate Na4Si04 Sodium Tripolyphosphate NasP 30-10 Ammonium Hydroxide NH4OH ... 

Moreover, although calcium carbonate scales can be successfully removed at production wells by acidizing or by using inhibitors, no long-term treatment exists to control silicate-containing precipitation. This is probably one reason that sodium orthosilicate is not frequently used in chemical flooding. Because of the plugging function, sodium silicate is mixed with calcium chloride alternately to improve sweep efficiency. 

Burk, J.H., 1987. Comparison of sodium carbonate, sodium hydroxide, and sodium orthosilicate for EOR. SPERE (February), 9-16. 

Novosad, Z., et al., 1981. Comparison of oil recovery potential of sodium orthosilicate and sodium hydroxide for the Wainwright reservoir, Alberta. Petroleum Recovery Institute Report No. 81-10 (July). 

All measurements were conducted in an aqueous alkaline solution of sodium orthosilicate unless otherwise indicated. The aqueous for all samples also had a 7500 ppm NaCl concentration, this being an optimum salt concentration to minimize sodium orthosilicate requirements. In all cases, the drop size was consistent and the data repeatable. 

Surface tension data were measured in both distilled water and 7500 ppm salt solution with an alkalinity of sodium orthosilicate ranging from 60 to 60,000 ppm. As an example, fractions of samples S-47 of the Lower Main Zone were investigated. 

Figure 13 exhibits both interfacial tension and electrophoretic mobility for the Huntington Beach Field crude oil against sodium orthosilicate containing no sodium chloride. The interfacial tension values are observed to be higher for the non-equilibrated sample in this case than for the caustic system reported in Figure 12. The minimum interfacial tension of 0.01 dynes/cm occurs at about 0.2% sodium silicate as opposed to a value of less than 0.002 dyne/cm at about 0.06% NaOH. It is interesting to note, however, that the maximum electrophoretic mobility is the same for the two systems. Once again, it should be noted that a maximum in electrophoretic mobility does not correspond to a minimum in interfacial tension for those samples which contained no sodium chloride.

Sodium orthosilicates are produced by blending ASM and NaOH beads or by fusion and grinding as in the direct manufacture of ASM. The relationships of these processes are shown in Figure 6. 

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